Have a look at Gigaset aka the Siemens branch that built all those DECT phones aka not Siemens mobile (which was a complete joke and failure). Not part of Siemens any more, anyway. Never really top of the line but also comparatively inexpensive (not as much as China phones but still), and most importantly: Replaceable battery. Always had them, even before the new EU regulation (which isn't even in force yet). Not really that popular in the mainstream market but definitely among builders etc. who want a rugged phone, they're quite successful in that niche.